Controlling mechanism for fluid-compressors.



0. H. & A. F. PIEPER.

CONTROLLING MECHANISM FOR FLUID COMPRESSORS.

APPLICATION FILED FEB. 7. 1914.

1,220,546. Patented Mar. 27, 1917.

3 SHEETS-SHEET I.

O. H. & A. F. PIEPER.

CONTROLLING MECHANISM FOR FLUID COMPRESSORS.

APPLICATION FILED FEB. 7. 1914.

1 ,220,546 Patented Mar. 27, 1917.

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Specification of Letters Patent.

Applicationnled February 7, 1914. Serial 80. 817,198.

declare the following .to be a full, clear, and exact description of the same, reference be- 'ing had to the accompanying drawings, forming a part of this specification, and to 4 the reference numerals marked thereon.

The present invention relates to automa tic controlling mechanisms for fluid com pressors, having reference more particularly to apparatus of the type embodying an air compressing pump operated by an electric motor, and means controlled by the pressure within the air supply tank for automatically stopping and starting the motor, whereby it is possible to maintain a substantially constant premre of air, and it has for its object to improve the construction of this class of apparatus in a manner which. will render the operation morepositive, and make the motor more responsive to the changes in pressure. A further purposeof the lnvention consists in providing a structure that will produce a more efficient cooperation between the fixed and movable contacts that control the motor, and reduce to a minimum the sparking, and fusing of the contacts, which takes place every time the'circuit ,is broken. To these and other ends the invention consists in certain improvements and combinations of parts all as will be hereinafter inore fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings: v

Figure 1 is a front elevation, with a portion of the control box broken away, showing the application of the invention, in-a they are 'moved from the position shown in Fig. 2 to that shown in Fig. 4;

- Fig. 6 is a vertical sectional view look-- ing in the opposite direction from that shown in Fig. 2; and 1 p Fig. 7 is a sectional view on the 1ine'7 ofFig.2.' .Q l p Similar reference characters throughout the-several figures indicate the same parts.

The present. embodiment shows a preferred arrangement of. the invention which it will be readily understood may be. carried out in various ways, and is applicable to any automatic controlling. .mechanism adapted to effect the making and breaking of a motor circuit by actuating a movable contact into and out, of engagementwvith a stationary contact, and as an illustration of one method of carrying out the invention, reference is had to an 2111' compressing apparatus, where the pump operating motor is controlled by air pressure, the movement of the motor being stopped when the pres sure rises beyond a certain predetermined point, and started again when it falls below such point. r i

Patented Mar. 27, 1917-.

In the construction shown, A designates;

.a tank or reservoir for containing the comressed fluid, and connected by means. of

t epipe a with the pump or compressor B I tionary contacts e within the controller box E, which are spring actuated and adapted to cooperate with the movableconta'ctefl the movable contact being held in engagement with the stationary contacts by the frictional engagement of the latter in the manner shown in Fig. 7.. The contact 6 is mounted upon a movable switch arm which is disconnected normally from the parts that effect its movement, and is adapted to be brought into and out of operative relation with the contacts '6' by a hammer-like blow, imparting a quick and decisive movement to the switch arm and thereby insuring an in stantaneous breaking of the motor circuit, while at once making it possible to maintain the contacts in firm and positive engagement with each other up to the moment of their separation. complished by a switch arm 0, which is pivotally mounted on the bearing a, and freely movable from the position shown in Fig. 2 to that shown in Fig. 4. The switch arm is provided with opposite portions adapted to be engaged by an actuator, which will presently be described, to efiect movement of the switch arm from one position to the other, its movement being limited in opposite direction by the stops a The opposite portions of the switch arm are preferably in the form of cam surfaces 6 e which are provided on the upper and lower extensions of the switch arm designated at e and e, the upper extension 6 having an end portion 6 for a purpose that will appear hereinafter.

The cam surfaces 6 6 permit the switch arm to be quickly controlled by the actuator and at the same time prevent undue shock between the parts, while they cause the actuator to engage the switch arm with a gradual effectiveness that imparts a smooth and easy action and insures closing the switch during the final movement of the actuator, which forces against said cam sur-- faces at the limit of its stroke and effects the completion of the movement of the switch arm.

The switch arm is moved-by means of an actuator designated at f, and pivoted at f, the actuator carrying a projection or antifriction roller f which is arranged to engage the cam surfaces 6 and 6" when the actuator is moved upwardly or downwardly. In order to impart the proper action to the switch arm it is necessary to impart a quick movement to the actuator, with sufficient force to cause it to deal a powerful blow to the switch arm, whereby the latter is knocked into and out of operative relation with the stationary contacts. By this means, the switch arm is entirely disconnected from the actuator, and free from tension at all times.

The actuator is operated from a controlling lever whose movement is determined by the fluid pressure inv the manner whichwill now be described. 9 designates the controlling lever pivotally mounted on the bearing 6 and connected to the actuator by a spring 9 which is movable to opposite sides of the axis of the actuator, that is to say from the position shown in Fig. 2 to that shown in Fig. 4;. The controlling lever g carries an extension g having a rounded portion 9 which is adapted to engage a recess or slot 9 of a pressure controlled member, or rod 9 The latter is connected to a pressure operated diaphragm 9 arranged in the chamber 9 which communicates with the pipe or by means of the passage 9 The diaphragm g is moved by the pressure of air, against the action of a spring 9 the tension of which may be adjusted by a plate 9 threaded on the rod 9 The casing E is provided with a Lemme recess or socket g to receive the end of the rod 9 and guide its movement back and forth. In the operation of the device, upon an increase of pressure, the diaphragm g and the rod 9 are moved inwardly, rocking the controlling lever 9 upon its axis from the uppermost position shown in Fig. 2 where the circuit is closed, until the spring 9 is moved to the opposite side of the axis of the actuator, on to the position shown substantially in Fig. 5. As soon as the spring reaches a position slightly beyond said axis, it pulls the actuator down to the position shown in Fig. 4: with a quick action, imparting a forceful blow to the lower portion 6 of the switch arm by coming in contact with the cam surface 6 and thus the switch arm is instantly knocked out of operative relation with the stationary contact, the circuit being broken. so quickly that no destructive sparking can occur. The weight of the switch arm holds it in its lowermost position, and upon a reduction of pressure,

the controlling lever g is moved in the opposite direction carrying the spring g upwardly again past the axis of the actuator, thereby causing the latter to be drawn upwardly, and to engage the upper cam surface 6 of the switch arm. This operation serves to throw the contact 6 upwardly between the stationary contacts 6', where it is held by frictional engagement until the operation is repeated. The movement of the actuator f upwardly and downwardly is limited by a pair of springs h which are carried by bolts 72/, adjustable in the bosses H.

In some instances, it happens that the contacts may be welded together to such an extent that the force of the actuator is not suflicient to disengage them, and under such the position shown in Fig. 4, by the actuator. It will be understood that under ordinary operating conditions the lug h performs no function, but when the contacts stick together, a sufficient increase of pressure will cause said lug to be forced against the switch arm, and effect disengagement of the contacts. The belt D is held in proper relation to its pulleys by means of a belt tightener F, mounted upon the shaft F which is arranged within the casing E, and controlled by the spring F to hold the tightener in engagement with the belt.

While the invention is described as applied to a particular type of machinery, it

is not limited in its application to the precise structure or combination of parts set forth, or to a pressure controlled apparatus,

and the present application is intended to cover any adaptations or modifications that will accomplish the purposes described, and are comprehended within the terms of the claims hereinafter.

lVe claim as our invention:

1. An automatic controlling mechanism for fluid compressors comprising in combination, a stationary electric contact and a movable contact cooperating therewith, a pivotally mounted switch arm carrying the movable contact and having opposed cam surfaces adjacent to and on opposite sides of its pivotal axis, an actuator pivotally mounted at a point removed from the pivotal axis of the switch arm and extending between said cam surfaces and cooperating alternately therewith to move the switch arm into and out of operative relation with the stationary contact, a pivoted controlling lever, a spring connecting the controlling lever and actuator and movable to opposite sides of the axis of the actuator, and a pressure controlled member governing the controlling lever.

2. An automatic. controlling mechanism,

- said cam surfaces to move the switch arm of the axis of the actuator, and a pressure controlled member governing the controlling lever.

3. An automatic controlling mechanism for fluid compressors comprising in combination, a stationary contact and a movable contact, a pivoted switch arm carrying the movable contact and having opposed cam surfaces adjacent to and on opposite sides of its pivotal axis, a pivotally mounted actuator cooperating with said cam surfaces alternately at the limit of its movement to actuate the switch arm into or out of'operative relation with the stationary contact, a pivoted controlling lever, a spring connecting the controlling lever and. actuator and movable to opposite sides of the axis of the actuator, a pressure controlled member governing the controlling lever, and means carried by the controlling lever and acting to engage the switch arm when the latter is not moved by the actuator.

4. An automatic controlling mechanism for fluid compressors comprising in combination, a stationary contact and a movable contact, a movable switch arm carrying the movable contact and having cam surfaces disposed at opposite points thereon, an actuator pivoted at a point remote from the pivotal axis of the switch arm and cooperating at the limit of its movement alternately with said cam surfaces to complete the movement of the switch arm, *and an automatically controlled means governing the actuator.

OSCAR H. PIEPER. ALPHONSE F. PIEPER.

Witnesses:

J. H. KLINE, R. W. STEWART. 

